Spark-plug



C. G. MINOR.

SPARK PLUG.

APPLICATION man MAR. 25.1920.

Patented Nov. 22, 1921.

:iii.

I VI T N [5 SS ES UNITED STATES cnAnLnse. MINOR, or DULUTH, MINNESOTA.

STARK-PLUG.

Specification of Letters Patent.

Patented Nov. 22, 1921.

Application filed March 25, 1920. Serial No. 368,502.

To all whom it may concern Be it known that I, CHARLES G. MINOR, a citizen of the United States, residing at Duluth, in the county of St. Louis and State of Minnesota, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a. specification, reference being had therein to the accompanying drawing.

This invention relates to spark plugs for internal combustion engines and has for its principal object improvements over those at present known in the art.

Another object is simplicity of construction.

Still other objects and advantages of the peculiar structure will appear in the further description of the invention.

Referring to the accompanying drawings forming part of this application and in which like reference characters indicate like parts:

Figure 1- is a central vertical sectional View partly in elevation of one of my improved plugs, and

Fig. 2 is a lowerend plan view.

Broadly, the invention resides in incasing both of the electrodes 1 and 2 of the spark plug within the porcelain or insulated core 3 'of the plug, and making the lower portion of the core, which extends within the lower end of the plug casing 4,as large as possible consistent with suflicient clearance to care for expansion et cetera, as well as making the lower end of the porcelain extend somewhat beyond the lower end of the plug, as clearly seen in the drawings.

The .core 3 is provided with the usual annular shoulders 5 and 6 and which is held in place Within the casing by the usual screw threaded gland 7. The upper end 8 of the electrode 2 which is the shorter one,

7 terminates in the shoulder 5 of the core and is impinged by the lower beveled edge of the gland 7 when the latter is screwed in place,

length of the porcelain and'is engaged at the upper end with the usual. thumb nut. As. before stated the lower end of the core extends beyond the lower end of the casing and the ends of the electrode project beyond the porcelain, they being each turned at right angles toward each other and one above the other as shown in Fig. 1 whereby the spark may occur either intermediate of the end of the shorter terminals and the vertical portion of the opposite electrode or between the two horizontal portions of the terminals, and the gap may be adjusted in the usual way by bending of either or both of the terminals.

Each electrode is surrounded by a conically shaped portion of the porcelain indicated at 10 as a preferred form of the'structure, which is found to assist in quickly heating the terminals and thus preventing the collection ofoil on the electrodesat the time of starting a cold engine.

The inner lower edge'of the plug is beveled as at 11 to further concentrate heat about the end of the core and insure non foulin of the terminals.

aving thus described my invention, whatI claim and desire to secure by Letters Patent, is:

. vertical portion of the opposite electrode or between the two horizontal portions of the terminals, substantially as described.

In testimony whereof I hereunto :aflix signature in the presence of two witnesses. CHARLES G. MINOR. Witnesses:

' H. L. LALIBERTE,

S. Gno. STEVENS- 

